In communication networks, such as telecommunication networks, a call or a service often involves, on the one hand, a control plane or signalling plane and, on the other hand, a user plane, media plane or traffic plane. The control plane or signalling plane is in charge of establishing and managing a connection between two points on the network. The user plane, media plane or traffic plane is in charge of transporting the user data.
In this context, network operators often want to define and enforce a set of rules in the network. A set of rules constitutes policies. A policy framework for managing and enforcing these policies usually includes at least three elements, or functions: a policy repository for storing the policy rules, which may be user-specific, a policy decision element, function or point, and a policy enforcement element, function or point. The purposes of a policy framework include controlling subscriber access to the networks and services.
A policy framework notably addresses the decisions as to whether the subscriber, i.e. the user, is entitled, or authorized, to enjoy a service, and whether the network can provide the service to the subscriber (and, possibly, with which quality of service).
Policy and charging control (PCC) architectures, such as, but not limited to, the architecture described in “3GPP TS 23.203 V11.6.0 (2012-June); Technical Specification; 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Policy and charging control architecture (Release 11)” (available on http://www.3gpp.org/ftp/Specs/html-info/23203.htm) (hereinafter referred to as “reference [1]”), integrate the policy and charging control.
In such a FCC architecture, a policy and charging rules function (PCRF) is a functional entity in charge of deciding charging, policies and quality of service (QoS) for services of a given user. The PCRF may for example decide the quality of the connection to be allocated for voice, video, etc., which results, for example, on the establishment of dedicated bearer(s) with guaranteed bit rate (GBR) or non-guaranteed bit rate (non GBR). The PCRF may also make decisions about packet forwarding treatment in the radio access network (RAN) by means of determining the QoS class identifier (QCI). The PCRF may also decide, at the packet core control plane, the priority of a bearer to be established over other bearers, for the same or different users, by providing allocation and retention priority (ARP) information. Based on the above decisions by the PCRF, PCC rules may be generated and then installed in a policy and charging enforcement function (PCEF) of the PCC architecture, so that each service is given the appropriate treatment that the service requires.
A TDF has been introduced in 3GPP specifications (Release 11) to cope with what is referred hereafter as “service awareness” functionalities. In other words, the need for a TDF stems from the insight that the operator of a telecommunications network might be interested in having specific policies with regard to data traffic relating to certain services that can be initiated or terminated by UEs of its subscribers, so as to e.g. enforce specific charging and/or QoS policies in respect to data flows relating to said services. A TDF is described for example in reference [1], sections 4.5 and 6.2.9.
How a PCRF may communicate with a PCEF and/or a TDF, for example via the so-called “Gx” and “Sd” interfaces, is for example described in “3GPP TS 29.212 V11.5.0 (2012-June); Technical Specification; 3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; Policy and Charging Control (PCC) over Gx/Sd reference point (Release 11)” (hereinafter referred to as “reference [2]”).
The background also includes European patent application EP 2 458 779 A1 (hereinafter referred to as “reference [3]” or “ref. [3]”), which relates to a PCC method enabling to monitor network resources usage on a per service instance basis, In one embodiment of ref. [3], a PCRF provides identification information for identifying a particular service instance of a particular service type to a PCEF to enable the PCEF to detect which of the received packets are associated with the service instance, so that a usage parameter can be updated. A usage limit may also be provided by the PCRF to the PCEF to enable the PCEF to decide when to report the usage parameter to the PCRF (ref. [3], paragraphs [0018] and [0044]). The identification information for identifying a particular service instance may be used to identify a particular (promoted) movie (ref. [3], paragraphs [0050], [0055], [0068], [0118], and [0137]).
It is desirable to provide methods and devices to improve PCC architectures and implementations, notably to provide more flexibility for operators in the manner according to which subscriber accesses may be controlled. There is also a constant need to keep the amount of network signalling as low as possible and even, if possible, to reduce the amount of network signalling involved.